Clean up guards for specs passing against PhantomJS

Author: p0deje

rb/spec/integration/selenium/webdriver/driver_spec.rb

@@ -277,7 +277,7 @@ def save_screenshot_and_assert(path)
         end
       end
 
-      describe 'execute async script', except: {browser: :phantomjs} do
+      describe 'execute async script' do
         before do
           driver.manage.timeouts.script_timeout = 0
           driver.navigate.to url_for('ajaxy_page.html')